CA1304918C - Porous mold for pressure slip casting, and method of making the same - Google Patents
Porous mold for pressure slip casting, and method of making the sameInfo
- Publication number
- CA1304918C CA1304918C CA000542851A CA542851A CA1304918C CA 1304918 C CA1304918 C CA 1304918C CA 000542851 A CA000542851 A CA 000542851A CA 542851 A CA542851 A CA 542851A CA 1304918 C CA1304918 C CA 1304918C
- Authority
- CA
- Canada
- Prior art keywords
- porous layer
- coarse
- porous
- mold
- adhesive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B1/00—Producing shaped prefabricated articles from the material
- B28B1/26—Producing shaped prefabricated articles from the material by slip-casting, i.e. by casting a suspension or dispersion of the material in a liquid-absorbent or porous mould, the liquid being allowed to soak into or pass through the walls of the mould; Moulds therefor ; specially for manufacturing articles starting from a ceramic slip; Moulds therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B1/00—Producing shaped prefabricated articles from the material
- B28B1/26—Producing shaped prefabricated articles from the material by slip-casting, i.e. by casting a suspension or dispersion of the material in a liquid-absorbent or porous mould, the liquid being allowed to soak into or pass through the walls of the mould; Moulds therefor ; specially for manufacturing articles starting from a ceramic slip; Moulds therefor
- B28B1/261—Moulds therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B1/00—Producing shaped prefabricated articles from the material
- B28B1/26—Producing shaped prefabricated articles from the material by slip-casting, i.e. by casting a suspension or dispersion of the material in a liquid-absorbent or porous mould, the liquid being allowed to soak into or pass through the walls of the mould; Moulds therefor ; specially for manufacturing articles starting from a ceramic slip; Moulds therefor
- B28B1/261—Moulds therefor
- B28B1/262—Mould materials; Manufacture of moulds or parts thereof
- B28B1/263—Plastics
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S425/00—Plastic article or earthenware shaping or treating: apparatus
- Y10S425/102—Air ejection
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Dispersion Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Producing Shaped Articles From Materials (AREA)
- Moulds, Cores, Or Mandrels (AREA)
- Ceramic Capacitors (AREA)
- Press-Shaping Or Shaping Using Conveyers (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Herein disclosed is a porous mold for pressure slip casting, which comprises: a surface porous layer having an average pore diameter of at most 20 microns and a thickness of 5 to 40 mm; an adhesive applied in a pattern to the rear surface of the surface porous layer to leave an unapplied portion on the rear surface; a coarse porous layer covering the adhesive applied and unapplied portions of the rear surface of the surface porous layer and made of a mixture of a liquid resin and a filler of a particle diameter of 0.1 to 5.0 mm at a volume ratio of 15 to 50 : 100, the coarse porous layer having a thickness of 5 to 30 mm; a sealing adhesive covering substantially the outer surface of the coarse porous layer; and means for passage of water from and air into the coarse porous layer. Also disclosed is a method of making the porous mold.
Herein disclosed is a porous mold for pressure slip casting, which comprises: a surface porous layer having an average pore diameter of at most 20 microns and a thickness of 5 to 40 mm; an adhesive applied in a pattern to the rear surface of the surface porous layer to leave an unapplied portion on the rear surface; a coarse porous layer covering the adhesive applied and unapplied portions of the rear surface of the surface porous layer and made of a mixture of a liquid resin and a filler of a particle diameter of 0.1 to 5.0 mm at a volume ratio of 15 to 50 : 100, the coarse porous layer having a thickness of 5 to 30 mm; a sealing adhesive covering substantially the outer surface of the coarse porous layer; and means for passage of water from and air into the coarse porous layer. Also disclosed is a method of making the porous mold.
Description
S P E C I F I C A T I O N
TITLE OF THE INVENTION
Porous Mold for Pressure Slip Casting, and Method of Making the Same BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to both a porous mold used in pressure slip casting and a method of making the porous mold.
Description of the Prior Art In the pressure casting process, the mold is required to have both passages for draining the water, which is forced from the molding surface of the mold into a porous layer, to the outside of the mold during high-pressure slip casting, and passages for supplying compressed air into the porous layer to spurt water or air from the molding surface through the porous layer when the cast product is to be removed from the mold.
Therefore, the mold used in the prior art is equipped with passages formed inside or at the rear surface of the porous layer to have communications with the outside of the mold.
As it now will be necessary to refer to the drawings, these will first be described as follows:
Figs. 1 to 3 are fragmentary views showing in section the porous molds according to the prior art;
Fig. 4 is a sectional view of a surface porous layer prepared in advance as a mold;
Fig. Sa is a top plan view of the surface porous layer placed on an under basic case;
Fig. Sb is a front elevation of the surface porous layer of Fig. 5a;
Fig. 6 shows how a porous mold according to the present invention is made on the under basic case; and Fig. 7 is a perspective view showing in a partial section the porous mold having a coarse layer on the rear surface thcreoe.
la '~'- ., .
~304918 BefGre entering into a detailed description of the present invention, cursory review of the prior art will be made in the following with reference to the accompanying drawings. Fig. 1 shows a mold which has channels 2 formed in the rear surface of a porous layer 1 as the passages. In a mold shown in Fig. 2, the channels 2 are formed in the porous layer 1 in parallel with the molding surface of the mold. In a mold shown in Fig. 3, the channels 2 extend into the porous layer 1 in relation perpendicular to the molding surface of the mold. In any of these examples, the porous layer 1 has its rear surface backed with a backing material 3.
1'hese channels are so accurately pitched and spaced from the molding surface of the mold that the water and air may be spurted evenly from the molding surface when the cast product is to be removed from the mold. As a result, the channels raise difficulties in making the porous mold. If the porous layer is made thinner, the water and air cannot be injected evenly from the inner surface of the porous layer, i.e., the molding surface of the mold unless of the channels have its smaller pitch. However, it is difficult to form the channels at a small interval.
This difficulty raises a defect that the porous layer has to be made thicker than necessary.
In order to overcome these defects, various molds have been proposed by Japanese Patent Laid-Open No.
17811 / 1973 and Japanese Patent Publication No. 14451 / 1981. According to the process disclosed in Japanese Patent Laid-Open No. 17811 / 1973, a two-layered structure is made by coating a mold of known plastic foam with a known porous material such as gypsum or the like. However, this process cannot control the pore diameter of the surface porous layer accurately but makes the surface porous layer excessively thin. From the restriction to the material of a coarse porous layer, moreover, this process is remarkably difficult to provide a mold for forming large-sized ceramic articles having a complicated shape.
Japanese Patent Publication No. 14451 / 1981 discloses a porous mold having a fine porous~layer and a coarse porous layer integrated with each other by press working and subsequent sintering. The porous layers are formed from a mixture of resin powder and filler powder, the fine porous layer has a thickness of 0.3 to 5 mm as a surface layer.
The pressing working, however, makes it remarkably difficult to make a large-sized mold having a complicated shape. It is also remarkably difficult to control the pore diameter of the surface porous layer i3~49~8 which plays an important role in the pressure slip casting process. Because of the sintering, moreover, dispersions may be incorporated into the sizing accuracy, strength and pore diameter so that the S process is not appropriate for making the mold for pressure casting of the large-sized ceramic articles having the complicated shape.
There can be conceived another process for making a mold by merely adhering a surface fine porous layer prepared in advance and a rear coarse porous layer also prepared in advance to each other by means of an adhesive which is applied in a linear or net pattern having appropriate interval and width. In making the large-sized and complicated mold, however, the adhesive may have a tendency to slip the surface fine porous layer and the rear coarse porous layer relative to each other. Then, the adhesive applied portion is so locally widended as to block the water and air spurting from the molding surface of the mold, when the cast product is to be removed from the mold, so that the conceived process cannot be used to make a practical mold.
According to another process conceivable, the coarse porous layer consisting of a mixture of a liquid adhesive and a filler of appropriate granularity is ~3049~8 adhered by a pressing or stamping method to the rear surface of a surface porous layer prepared in advance.
Because of a low adhesion between the surface porous layer and the coarse porous layer, however, this process cannot make a practical mold capable of standing an actual use.
SUMMARY OF TEE INVENTION
It is, therefore, an object of an aspect of the present invention to provide a porous mold which is made by forming a coarse porous layer on the rear surface of a porous layer prepared in advance as a mold and which is suited for pressure casting large-sized ceramic articles having a complicated shape.
An object of an aspect of the invention is to provide a method of making the above-specified porous mold.
According to one ~eature of the present invention, there i~ provided a porous mold for pressure s}ip casting, comprising: a surface porous layer having an average pore diameter of at most 20 microns and a thickness of 5 to 40 mm; an adhesive applied in a pattern to the rear surface of said surface porous layer to leave an unapplied portion on said rear surface; a coarse porous layer covering he adhesive applied and unapplied portions of the rear surface of ,:
. ~
13049~8 said surface porous layer and made of a mixture of a liquid resin and a filler of a particLe size of 0.1 to 5.0 mm at a volume ratio of 15 to 50 : 100, said coarse porous layer having a thickness of 5 to 30 mm ; a sealing adhesive resin covering substantially the outer surface of said coarse porous layer; and means for passage of water from and air into said coarse porous layer.
According to another feature of the present invention, there is provided a method making a porous mold, comprising the steps of: casting a surface porous layer having an average pore diameter of at most 20 microns and a thickness of 5 to 40 mm; applying an adhesive in a pattern to the rear surface of said surface porous layer to }eave an unapplied portion on said rear surface; forming on the adhesive applied and unapplied portions of the rea~ surface of said surface porous layer a coarse porous layer made of a mixture of a liquid resin and a filter of a particle size of 0.1 to 5.0 mm at a volume ratio of 15 to 50 : 100, said coarse porous layer having a thickness of 5 to 30 mm;
substantially sealing the outer surface of said coarse porous layer with a sealing adhesive resin after the first adhesive and said coarse porous layer have cured and connecting at least one pipe to said coarse porous .. ~
:
`:
13~4918 layer for passage of water from and air into said coarse porous layer.
DESCRIPTION OF TH~ PR$YERRYD E~BODIMENT
A method making a porous mold according to the S present invention will be described in the following 13~49J 8 with reference to the accompanying drawings.
Fig. 4 shows in section the surface porous layer 1 which has been prepared as a mold in advance. This surface porous layer 1 has a molding surface 5 and an opposite rear surface 6 of the mold. Prior to application of an adhesive, as shown in Figs. 5a and 5b, the surface porous layer 1 is placed on an under basic case 9 with the molding surface 5 directed downward. Then, an adhesive is applied in a net pattern to the rear surface 6 of the surface porous layer 1 so that the rear surface 6 is patterned with an applied adhesive net 7 and an unapplied ground 8.
Then, a coarse porous layer 10 composed of a mixture of a resin and a filler is pressed or stamped onto the rear surface 6 of the surface porous layer 1 so that it is firmly adhered to the surface porous layer 1 by the intervening adhesive net 7. Fluid communication is provided between the coarse porous layer 10 and the surface porous layer 1 through the unapplied ground 8.
As shown in Figs. 6 and 7, a pipe 11 for passage of water/air is connected to the coarse porous layer 10, and a seaIing adhesive resin 12 is applied to the outer surface of the coarse porous layer 10 and the exposed surface of the under basic case 9. Then, a reinforcing iron frame 13 is placed on the under basic 130~918 case 9 and filled up with a filler or filling material 14.
The porous mold thus made according to the present invention is used as a pr'essure casting mold for ceramic articles, which is constructed by fitting it in the reinforcin~ iron frame or in a pressure-resisting container and by filling up the space between the porous mold and that reinforcing structure with the filler or filling material.
In the present invention, the surface porous layer is cast in advance to have a pore diameter of 20 microns or less. If this pore diameter is exceeded, the surface porous layer fails to act as a pressure casting filter material. On the other hand, the thickness of the surface porous layer is selected to be S to 40 mm. This selection is made partly because the surface porous layer thinner than 5 mm will make it difficult to spurt tbé water and air evenly from the ': molding surface when the,cast product is to be removed ' ~20 from the mold and partly because the surface porous layer thicker than 40 mm will have its compression deformation increased by the slip pressure during the ,: pressure casting operation to invite defects that the ,: reaction due to the increased compression deformation : ~ 25 causes the porous layer to bite the product thereby to '~ _ g _ .
make it reluctant to part the product and that the increased compression deformation makes it liable to crack the corner or corners of the mold. With these being considered together with one of the advantages of the present invention, it is concluded that the porous layer may preferably be 10 to 20 mm thick.
Next, the adhesive to be applied to the rear surface of the surface porous layer for adhering the surface porous layer and the coarse porous layer to be formed later may be suitably exemplified by a cold curing type epoxy resin, to which the present invention should not be limited. The coarse porous layer acts to provide passages for allowing thP water and air to pass therethrough. The applied adhesion net and the unapplied ground between thQ surface and coarse porous layers should be so balanced that the water and air may be spurted evenly from the molding surface of the ; surface porous layer when compressed air is forced into the coarse porous layer to release the product from the mold, for example. In other words, neither the applied portion nor the unapplied portion should be excessively wide even locally. It is therefore desirable that the width of each adhesive applied be two times or less as large as the thickness of the surface porous layer.
The larger width will locally leave such a portion or 13049i8 portions on the molding surface as obstructs the passage of the water and air to invite a difficulty in the product releasing action.
If, on the contrary, the unapplied portion or portions are excessively enlarged or widened locally, the surface porous layer will possibly be broken by the pressure of the compressed air for releasing the product. The maximum area, width and so on of the unapplied portion or portions may be determined depending upon the strength and thickness of the surface porous layer and the coarse porous layer and upon the product releasing air pressure. Therefore, the adhesion should be applied in the net pattern or in a linear or dot pattern so that the width o~ area of the unapplied ground may be as even as possible.
Next, the applied portion or portions are required to have such area and evenness that they may not be ; separated at their interfaces with the surface porous layer or the coarse porous layer by the compressed air supplied for releasing the product. In this case, too, the ratio of the area to which the adhesive is applied is determined depending upon the tensile strengths of the surface porous layer and the coarse porous layer and upon the product releasing air pressure.
On the other hand, the filler or filling material 13~49~8 to form the coarse porous layer has a particle diameter of 0.1 to 0.5 mm so as to form a coarse porous layer having an average pore diameter of 100 microns or more.
This filler is mixed with a liquid resin to prepare a S mixture for forming the coarse porous layer. The mixing volume ratio of the liquid resin to the filler is within a range of 15 to 50 : 100. The ratio lower than 15 ~ will degrade the strength of the coarse porous layer and make it difficult to form the coarse layer. The ratio higher than 50 % will allow the li~uid adhesive to stick to the rear surface of the surface porous layer so that the water and air communications between the coarse porous layer and the surface porous layer are blocked to invite troubles lS when the product is to be removed.
Next, the coarse porous layer is desired to have a thickness of 5 to 30 mm. The thickness smaller than 5 mm will make the coarse porous layer itself difficult to form. On the other hand, the thickness larger than 30 mm will make nonsense for providing the water/air communication passages. In addition, the coarse porous layer will be subjected to a compression deformation, during the pressure casting process, if it is excessively thick, thus raising the aforementioned troubles. In the present invention, on the other hand, the coarse porous layer has its filler selected to have a particle size of 0.1 to 5.0 mm so that its average pore diameter is 100 microns or more. The average pore diameter below this value would result in increased resistance to the passage of air. This invites another disadvantage that an increased number of pipes for providing communications with the outside of the mold have to be connected to the coarse porous layer.
The materials to be used to make the porous mold according to the present invention will be specified in the following. The adhesive 7 may be one known under the trade mark of "Adhesive Bond E250"TM produced by Konishi Kabushiki Kaisha. The resin or one component of the coarse porous layer 10 may be a mixture of an epoxy resin known under the trade mark of "Epikote 815"TM and a curing agent known under the trade mark of "Epomate B002"TM produced by Yuka Shell Epoxy Kabushiki Kaisha.
The filler or another component of the coarse porous layer 10 may be quartz sand having a particle size of 0.1 to 5 mm. The sealing adhesive resin 12 may be one known under the trade mark of "Adhesive Bond E250"TM
produced by Konishi Kabushiki Kaisha. The filler 14 may be cement mortar or concrete.
According to the present invention, as has been described hereinbefore, the adhesive is preferably .
i30491~
applied in the net, linear or dot pattern to the porous layer, which has been prepared as the mold in advance, so that the net, linear or dot pattern may be adhered while the coarse porous Layer is being formed. As a S result, it is possible to provide without difficulty the porous mold which is suited for pressure casting the large-sized ceramic articles having a complicated shape. Moreover, the water/air communications between the two porous layers are improved while preventing the water and air from leaking to the outside by the sealing adhesive resin cover. As a result, the water and air are allowed to spurt evenly from the molding surface so that the product can be effectively removed from the mold.
Thus, the present invention can provide both the porous mold, which can be used for pressure casting ceramic articles and a method of making the porous mold.
TITLE OF THE INVENTION
Porous Mold for Pressure Slip Casting, and Method of Making the Same BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to both a porous mold used in pressure slip casting and a method of making the porous mold.
Description of the Prior Art In the pressure casting process, the mold is required to have both passages for draining the water, which is forced from the molding surface of the mold into a porous layer, to the outside of the mold during high-pressure slip casting, and passages for supplying compressed air into the porous layer to spurt water or air from the molding surface through the porous layer when the cast product is to be removed from the mold.
Therefore, the mold used in the prior art is equipped with passages formed inside or at the rear surface of the porous layer to have communications with the outside of the mold.
As it now will be necessary to refer to the drawings, these will first be described as follows:
Figs. 1 to 3 are fragmentary views showing in section the porous molds according to the prior art;
Fig. 4 is a sectional view of a surface porous layer prepared in advance as a mold;
Fig. Sa is a top plan view of the surface porous layer placed on an under basic case;
Fig. Sb is a front elevation of the surface porous layer of Fig. 5a;
Fig. 6 shows how a porous mold according to the present invention is made on the under basic case; and Fig. 7 is a perspective view showing in a partial section the porous mold having a coarse layer on the rear surface thcreoe.
la '~'- ., .
~304918 BefGre entering into a detailed description of the present invention, cursory review of the prior art will be made in the following with reference to the accompanying drawings. Fig. 1 shows a mold which has channels 2 formed in the rear surface of a porous layer 1 as the passages. In a mold shown in Fig. 2, the channels 2 are formed in the porous layer 1 in parallel with the molding surface of the mold. In a mold shown in Fig. 3, the channels 2 extend into the porous layer 1 in relation perpendicular to the molding surface of the mold. In any of these examples, the porous layer 1 has its rear surface backed with a backing material 3.
1'hese channels are so accurately pitched and spaced from the molding surface of the mold that the water and air may be spurted evenly from the molding surface when the cast product is to be removed from the mold. As a result, the channels raise difficulties in making the porous mold. If the porous layer is made thinner, the water and air cannot be injected evenly from the inner surface of the porous layer, i.e., the molding surface of the mold unless of the channels have its smaller pitch. However, it is difficult to form the channels at a small interval.
This difficulty raises a defect that the porous layer has to be made thicker than necessary.
In order to overcome these defects, various molds have been proposed by Japanese Patent Laid-Open No.
17811 / 1973 and Japanese Patent Publication No. 14451 / 1981. According to the process disclosed in Japanese Patent Laid-Open No. 17811 / 1973, a two-layered structure is made by coating a mold of known plastic foam with a known porous material such as gypsum or the like. However, this process cannot control the pore diameter of the surface porous layer accurately but makes the surface porous layer excessively thin. From the restriction to the material of a coarse porous layer, moreover, this process is remarkably difficult to provide a mold for forming large-sized ceramic articles having a complicated shape.
Japanese Patent Publication No. 14451 / 1981 discloses a porous mold having a fine porous~layer and a coarse porous layer integrated with each other by press working and subsequent sintering. The porous layers are formed from a mixture of resin powder and filler powder, the fine porous layer has a thickness of 0.3 to 5 mm as a surface layer.
The pressing working, however, makes it remarkably difficult to make a large-sized mold having a complicated shape. It is also remarkably difficult to control the pore diameter of the surface porous layer i3~49~8 which plays an important role in the pressure slip casting process. Because of the sintering, moreover, dispersions may be incorporated into the sizing accuracy, strength and pore diameter so that the S process is not appropriate for making the mold for pressure casting of the large-sized ceramic articles having the complicated shape.
There can be conceived another process for making a mold by merely adhering a surface fine porous layer prepared in advance and a rear coarse porous layer also prepared in advance to each other by means of an adhesive which is applied in a linear or net pattern having appropriate interval and width. In making the large-sized and complicated mold, however, the adhesive may have a tendency to slip the surface fine porous layer and the rear coarse porous layer relative to each other. Then, the adhesive applied portion is so locally widended as to block the water and air spurting from the molding surface of the mold, when the cast product is to be removed from the mold, so that the conceived process cannot be used to make a practical mold.
According to another process conceivable, the coarse porous layer consisting of a mixture of a liquid adhesive and a filler of appropriate granularity is ~3049~8 adhered by a pressing or stamping method to the rear surface of a surface porous layer prepared in advance.
Because of a low adhesion between the surface porous layer and the coarse porous layer, however, this process cannot make a practical mold capable of standing an actual use.
SUMMARY OF TEE INVENTION
It is, therefore, an object of an aspect of the present invention to provide a porous mold which is made by forming a coarse porous layer on the rear surface of a porous layer prepared in advance as a mold and which is suited for pressure casting large-sized ceramic articles having a complicated shape.
An object of an aspect of the invention is to provide a method of making the above-specified porous mold.
According to one ~eature of the present invention, there i~ provided a porous mold for pressure s}ip casting, comprising: a surface porous layer having an average pore diameter of at most 20 microns and a thickness of 5 to 40 mm; an adhesive applied in a pattern to the rear surface of said surface porous layer to leave an unapplied portion on said rear surface; a coarse porous layer covering he adhesive applied and unapplied portions of the rear surface of ,:
. ~
13049~8 said surface porous layer and made of a mixture of a liquid resin and a filler of a particLe size of 0.1 to 5.0 mm at a volume ratio of 15 to 50 : 100, said coarse porous layer having a thickness of 5 to 30 mm ; a sealing adhesive resin covering substantially the outer surface of said coarse porous layer; and means for passage of water from and air into said coarse porous layer.
According to another feature of the present invention, there is provided a method making a porous mold, comprising the steps of: casting a surface porous layer having an average pore diameter of at most 20 microns and a thickness of 5 to 40 mm; applying an adhesive in a pattern to the rear surface of said surface porous layer to }eave an unapplied portion on said rear surface; forming on the adhesive applied and unapplied portions of the rea~ surface of said surface porous layer a coarse porous layer made of a mixture of a liquid resin and a filter of a particle size of 0.1 to 5.0 mm at a volume ratio of 15 to 50 : 100, said coarse porous layer having a thickness of 5 to 30 mm;
substantially sealing the outer surface of said coarse porous layer with a sealing adhesive resin after the first adhesive and said coarse porous layer have cured and connecting at least one pipe to said coarse porous .. ~
:
`:
13~4918 layer for passage of water from and air into said coarse porous layer.
DESCRIPTION OF TH~ PR$YERRYD E~BODIMENT
A method making a porous mold according to the S present invention will be described in the following 13~49J 8 with reference to the accompanying drawings.
Fig. 4 shows in section the surface porous layer 1 which has been prepared as a mold in advance. This surface porous layer 1 has a molding surface 5 and an opposite rear surface 6 of the mold. Prior to application of an adhesive, as shown in Figs. 5a and 5b, the surface porous layer 1 is placed on an under basic case 9 with the molding surface 5 directed downward. Then, an adhesive is applied in a net pattern to the rear surface 6 of the surface porous layer 1 so that the rear surface 6 is patterned with an applied adhesive net 7 and an unapplied ground 8.
Then, a coarse porous layer 10 composed of a mixture of a resin and a filler is pressed or stamped onto the rear surface 6 of the surface porous layer 1 so that it is firmly adhered to the surface porous layer 1 by the intervening adhesive net 7. Fluid communication is provided between the coarse porous layer 10 and the surface porous layer 1 through the unapplied ground 8.
As shown in Figs. 6 and 7, a pipe 11 for passage of water/air is connected to the coarse porous layer 10, and a seaIing adhesive resin 12 is applied to the outer surface of the coarse porous layer 10 and the exposed surface of the under basic case 9. Then, a reinforcing iron frame 13 is placed on the under basic 130~918 case 9 and filled up with a filler or filling material 14.
The porous mold thus made according to the present invention is used as a pr'essure casting mold for ceramic articles, which is constructed by fitting it in the reinforcin~ iron frame or in a pressure-resisting container and by filling up the space between the porous mold and that reinforcing structure with the filler or filling material.
In the present invention, the surface porous layer is cast in advance to have a pore diameter of 20 microns or less. If this pore diameter is exceeded, the surface porous layer fails to act as a pressure casting filter material. On the other hand, the thickness of the surface porous layer is selected to be S to 40 mm. This selection is made partly because the surface porous layer thinner than 5 mm will make it difficult to spurt tbé water and air evenly from the ': molding surface when the,cast product is to be removed ' ~20 from the mold and partly because the surface porous layer thicker than 40 mm will have its compression deformation increased by the slip pressure during the ,: pressure casting operation to invite defects that the ,: reaction due to the increased compression deformation : ~ 25 causes the porous layer to bite the product thereby to '~ _ g _ .
make it reluctant to part the product and that the increased compression deformation makes it liable to crack the corner or corners of the mold. With these being considered together with one of the advantages of the present invention, it is concluded that the porous layer may preferably be 10 to 20 mm thick.
Next, the adhesive to be applied to the rear surface of the surface porous layer for adhering the surface porous layer and the coarse porous layer to be formed later may be suitably exemplified by a cold curing type epoxy resin, to which the present invention should not be limited. The coarse porous layer acts to provide passages for allowing thP water and air to pass therethrough. The applied adhesion net and the unapplied ground between thQ surface and coarse porous layers should be so balanced that the water and air may be spurted evenly from the molding surface of the ; surface porous layer when compressed air is forced into the coarse porous layer to release the product from the mold, for example. In other words, neither the applied portion nor the unapplied portion should be excessively wide even locally. It is therefore desirable that the width of each adhesive applied be two times or less as large as the thickness of the surface porous layer.
The larger width will locally leave such a portion or 13049i8 portions on the molding surface as obstructs the passage of the water and air to invite a difficulty in the product releasing action.
If, on the contrary, the unapplied portion or portions are excessively enlarged or widened locally, the surface porous layer will possibly be broken by the pressure of the compressed air for releasing the product. The maximum area, width and so on of the unapplied portion or portions may be determined depending upon the strength and thickness of the surface porous layer and the coarse porous layer and upon the product releasing air pressure. Therefore, the adhesion should be applied in the net pattern or in a linear or dot pattern so that the width o~ area of the unapplied ground may be as even as possible.
Next, the applied portion or portions are required to have such area and evenness that they may not be ; separated at their interfaces with the surface porous layer or the coarse porous layer by the compressed air supplied for releasing the product. In this case, too, the ratio of the area to which the adhesive is applied is determined depending upon the tensile strengths of the surface porous layer and the coarse porous layer and upon the product releasing air pressure.
On the other hand, the filler or filling material 13~49~8 to form the coarse porous layer has a particle diameter of 0.1 to 0.5 mm so as to form a coarse porous layer having an average pore diameter of 100 microns or more.
This filler is mixed with a liquid resin to prepare a S mixture for forming the coarse porous layer. The mixing volume ratio of the liquid resin to the filler is within a range of 15 to 50 : 100. The ratio lower than 15 ~ will degrade the strength of the coarse porous layer and make it difficult to form the coarse layer. The ratio higher than 50 % will allow the li~uid adhesive to stick to the rear surface of the surface porous layer so that the water and air communications between the coarse porous layer and the surface porous layer are blocked to invite troubles lS when the product is to be removed.
Next, the coarse porous layer is desired to have a thickness of 5 to 30 mm. The thickness smaller than 5 mm will make the coarse porous layer itself difficult to form. On the other hand, the thickness larger than 30 mm will make nonsense for providing the water/air communication passages. In addition, the coarse porous layer will be subjected to a compression deformation, during the pressure casting process, if it is excessively thick, thus raising the aforementioned troubles. In the present invention, on the other hand, the coarse porous layer has its filler selected to have a particle size of 0.1 to 5.0 mm so that its average pore diameter is 100 microns or more. The average pore diameter below this value would result in increased resistance to the passage of air. This invites another disadvantage that an increased number of pipes for providing communications with the outside of the mold have to be connected to the coarse porous layer.
The materials to be used to make the porous mold according to the present invention will be specified in the following. The adhesive 7 may be one known under the trade mark of "Adhesive Bond E250"TM produced by Konishi Kabushiki Kaisha. The resin or one component of the coarse porous layer 10 may be a mixture of an epoxy resin known under the trade mark of "Epikote 815"TM and a curing agent known under the trade mark of "Epomate B002"TM produced by Yuka Shell Epoxy Kabushiki Kaisha.
The filler or another component of the coarse porous layer 10 may be quartz sand having a particle size of 0.1 to 5 mm. The sealing adhesive resin 12 may be one known under the trade mark of "Adhesive Bond E250"TM
produced by Konishi Kabushiki Kaisha. The filler 14 may be cement mortar or concrete.
According to the present invention, as has been described hereinbefore, the adhesive is preferably .
i30491~
applied in the net, linear or dot pattern to the porous layer, which has been prepared as the mold in advance, so that the net, linear or dot pattern may be adhered while the coarse porous Layer is being formed. As a S result, it is possible to provide without difficulty the porous mold which is suited for pressure casting the large-sized ceramic articles having a complicated shape. Moreover, the water/air communications between the two porous layers are improved while preventing the water and air from leaking to the outside by the sealing adhesive resin cover. As a result, the water and air are allowed to spurt evenly from the molding surface so that the product can be effectively removed from the mold.
Thus, the present invention can provide both the porous mold, which can be used for pressure casting ceramic articles and a method of making the porous mold.
Claims (13)
1. A porous mold for pressure slip casting, comprising:
a surface porous layer having an average pore diameter of at most 20 microns and a thickness of 5 to 40 mm;
an adhesive applied in a pattern to the rear surface of said surface porous layer to leave an unapplied portion on said rear surface;
a coarse porous layer covering the adhesive applied and unapplied portions of the rear surface of said surface porous layer and made of a mixture of a liquid resin and a filler of a particle size of 0.1 to 5.0 mm at a volume ratio of 15 to 50 : 100, said coarse porous layer having a thickness of 5 to 30 mm ;
a sealing adhesive resin covering substantially the outer surface of said coarse porous layer; and means for passage of water from and air into said coarse porous layer.
a surface porous layer having an average pore diameter of at most 20 microns and a thickness of 5 to 40 mm;
an adhesive applied in a pattern to the rear surface of said surface porous layer to leave an unapplied portion on said rear surface;
a coarse porous layer covering the adhesive applied and unapplied portions of the rear surface of said surface porous layer and made of a mixture of a liquid resin and a filler of a particle size of 0.1 to 5.0 mm at a volume ratio of 15 to 50 : 100, said coarse porous layer having a thickness of 5 to 30 mm ;
a sealing adhesive resin covering substantially the outer surface of said coarse porous layer; and means for passage of water from and air into said coarse porous layer.
2. A porous mold according to Claim 1, wherein said means includes at least one pipe connected to said coarse porous layer.
3. A porous mold according to Claim 1, wherein said pattern is selected from the group consisting of net, linear and dot patterns.
4. A porous mold according to Claim 1, wherein said coarse porous layer is pressed onto said surface porous layer.
5. A porous mold according to Claim 1, wherein said coarse porous layer is stamped onto said cource porous layer.
6. A porous mold according to Claim 1, wherein said coarse porous layer has an average pore diameter of at least 100 microns.
7. A porous mold according to Claim 1, wherein the pattern of said adhesive has a width at most two times as large as the thickness of said surface porous layer.
8. A method of making a porous mold, comprising the steps of:
casting a surface porous layer having an average pore diameter of at most 20 microns and a thickness of S to 40 mm;
applying an adhesive in a pattern to the rear surface of said surface porous layer to leave an unapplied portion on said rear surface;
forming on the adhesive applied and unapplied portions of the rear surface of said surface porous layer a coarse porous layer made of a mixture of a liquid resin and a filter of a particle size of 0.1 to 5.0 mm at a volume ratio of 15 to 50 : 100, said coarse porous layer having a thickness of 5 to 30 mm;
substantially sealing the outer surface of said coarse porous layer with a sealing adhesive resin after the first adhesive and said coarse porous layer have cured; and connecting at least one pipe to said coarse porous layer for passage of water from and air into said coarse porous layer.
casting a surface porous layer having an average pore diameter of at most 20 microns and a thickness of S to 40 mm;
applying an adhesive in a pattern to the rear surface of said surface porous layer to leave an unapplied portion on said rear surface;
forming on the adhesive applied and unapplied portions of the rear surface of said surface porous layer a coarse porous layer made of a mixture of a liquid resin and a filter of a particle size of 0.1 to 5.0 mm at a volume ratio of 15 to 50 : 100, said coarse porous layer having a thickness of 5 to 30 mm;
substantially sealing the outer surface of said coarse porous layer with a sealing adhesive resin after the first adhesive and said coarse porous layer have cured; and connecting at least one pipe to said coarse porous layer for passage of water from and air into said coarse porous layer.
9. A porous mold making method according to Claim 8, wherein said pattern is selected from the group consisting of net, linear and dot patterns.
10. A porous mold making method according to Claim 8, the coarse porous layer forming step includes the sub-step of pressing said coarse porous layer onto said surface porous layer.
11. A porous mold making method according to Claim 8, the coarse porous layer forming step includes the sub-step of stamping said coarse porous layer onto said surface porous layer.
12. A porous mold making method according to Claim 8, wherein said coarse porous Layer has an average pore diameter of at least 100 microns.
13. A porous mold making method according to Claim 8, wherein the pattern of said adhesive has a width at most two times as large as the thickness of said surface porous layer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP176370/1986 | 1986-07-26 | ||
| JP61176370A JPS6331710A (en) | 1986-07-26 | 1986-07-26 | Manufacture of porous mold for pressure-molding pottery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1304918C true CA1304918C (en) | 1992-07-14 |
Family
ID=16012434
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000542851A Expired - Fee Related CA1304918C (en) | 1986-07-26 | 1987-07-23 | Porous mold for pressure slip casting, and method of making the same |
Country Status (9)
| Country | Link |
|---|---|
| US (2) | US4913868A (en) |
| JP (1) | JPS6331710A (en) |
| KR (1) | KR900003082B1 (en) |
| CA (1) | CA1304918C (en) |
| DE (1) | DE3724610A1 (en) |
| FR (1) | FR2601895B1 (en) |
| GB (1) | GB2194751B (en) |
| IT (1) | IT1222130B (en) |
| SE (1) | SE468380B (en) |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5156856A (en) * | 1986-12-04 | 1992-10-20 | Ngk Insulators, Ltd. | Mold for forming molded body |
| KR910002176B1 (en) * | 1988-02-26 | 1991-04-06 | 가부시기가이샤 이낙스 | Gas-permeable porousbody its production and pressure casting mold |
| JPH0512001Y2 (en) * | 1988-07-19 | 1993-03-26 | ||
| US5356578A (en) * | 1988-08-08 | 1994-10-18 | Kawasaki Steel Corporation | Mold for slip casting and method of slip casting |
| US5451152A (en) * | 1989-06-21 | 1995-09-19 | Ngk Insulators, Ltd. | Porous mold for manufacturing ceramics |
| JPH03104604A (en) * | 1989-09-19 | 1991-05-01 | Ngk Insulators Ltd | Manufacture of mold for hollow insert ceramic body and manufacture of hollow insert ceramic body using mold |
| JPH03108503A (en) * | 1989-09-22 | 1991-05-08 | Inax Corp | Molding method for forming mold for pressure casting |
| IT1247096B (en) * | 1991-01-23 | 1994-12-12 | Nassetti Ettore Spa | METHOD OF MAKING A MOLD AND MOLD ACCORDING TO THIS METHOD FOR THE FORMING OF CERAMIC PRODUCTS, PARTICULARLY SANITARY PRODUCTS. |
| JP2808211B2 (en) * | 1992-06-09 | 1998-10-08 | 東陶機器 株式会社 | Continuous pore porous body and pressure casting mold for porcelain using the porous body |
| DE4225412C1 (en) * | 1992-07-31 | 1993-04-29 | Willi 8905 Mering De Roth | |
| US5427722A (en) * | 1993-06-11 | 1995-06-27 | General Motors Corporation | Pressure slip casting process for making hollow-shaped ceramics |
| JP2870445B2 (en) * | 1995-02-20 | 1999-03-17 | ソニー株式会社 | Mold formed by additive manufacturing and method of forming the same |
| US5916599A (en) * | 1996-11-14 | 1999-06-29 | Illinois Institute Of Technology | Apparatus for generating generally uniform compression in high-viscosity liquids |
| DE19854258A1 (en) * | 1998-11-25 | 2000-05-31 | Univ Ilmenau Tech | Pressure casting tool for shaping ceramics has coating on inner surface of tool forming mold volume that maintains pores open and hence filtration characteristics of tool |
| US6531078B2 (en) * | 2001-02-26 | 2003-03-11 | Ahlstrom Glassfibre Oy | Method for foam casting using three-dimensional molds |
| ITRE20010022A1 (en) * | 2001-03-09 | 2002-09-09 | Sacmi | MOLD ELEMENT FOR THE FORMING OF OBJECTS BY MELTING WITH A CLAY HUMID DOUGH AND SIMILAR AND METHOD FOR ITS MANUFACTURE |
| US6408567B1 (en) * | 2001-03-12 | 2002-06-25 | Knight Manufacturing Co., Inc. | Fishing lures and methods and molds for making same |
| EP1817146B1 (en) * | 2004-11-25 | 2013-01-02 | Dorst Technologies GmbH & Co. KG | Casting mold, especially diecasting mold, method for producing the same and method for low pressure diecasting |
| DE102004056975B3 (en) * | 2004-11-25 | 2006-07-06 | Dorst Technologies Gmbh & Co. Kg | Casting mold used as a die casting mold comprises a base layer made from firmly interlinked bulk material having a base layer permeability and a filter layer penetrating the surface of the base layer |
| DE102005038887A1 (en) * | 2005-08-17 | 2007-03-01 | Dorst Technologies Gmbh & Co. Kg | Casting mold used as a die casting mold comprises a base layer made from firmly interlinked bulk material having a base layer permeability and a filter layer penetrating the surface of the base layer |
| DE102007045806A1 (en) | 2007-09-25 | 2009-04-02 | Dorst Technologies Gmbh & Co. Kg | Molded component, particularly compressed molded component, has base layer that is made of base layer material of firmly connected pieces, and base layer material has base layer permeability that is dimensioned for conducting fluid |
| DE102009007670A1 (en) | 2009-02-05 | 2010-08-12 | Dorst Technologies Gmbh & Co. Kg | Mold component, mold and use of such a mold |
| CN103722615B (en) * | 2014-01-10 | 2017-03-29 | 兆峰陶瓷（北京）洁具有限公司 | For making Belt-type tools of cleaners and polishes and preparation method thereof |
| US11305457B2 (en) * | 2019-05-03 | 2022-04-19 | James R. Glidewell Dental Ceramics, Inc. | Pressure casting of submicron ceramic particles and methods of ejection |
Family Cites Families (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB661780A (en) * | 1949-03-28 | 1951-11-28 | Sintered Products Ltd | Improvements in or relating to moulds |
| GB808217A (en) * | 1955-03-29 | 1959-01-28 | Heinz Sieprath | Mould for producing castings, especially from ceramic raw stock |
| FR1144917A (en) * | 1955-03-29 | 1957-10-18 | Casting mold for objects of specific shape, in particular of a ceramic raw material | |
| US3243860A (en) * | 1961-11-07 | 1966-04-05 | American Radiator & Standard | Molding methods and associated apparatus |
| GB1295055A (en) * | 1969-08-19 | 1972-11-01 | ||
| CH490960A (en) * | 1969-12-02 | 1970-05-31 | Inventa Ag | Process for the production of absorbent capillary-active molded bodies |
| US3723584A (en) * | 1969-12-15 | 1973-03-27 | Bischoff Chemical Corp | Method of making an electroformed mold having heat transfer conduits and foam polyurethane foundation |
| US3755213A (en) * | 1971-03-22 | 1973-08-28 | Wallace Murray Corp | Porous resin bonded product |
| US3929685A (en) * | 1971-12-23 | 1975-12-30 | Bruno Jung | Process for producing casting molds suitable for use in the ceramic industry |
| US3993727A (en) * | 1974-12-18 | 1976-11-23 | Wallace-Murray Corporation | Fluid-release mold and the method of manufacturing the same |
| JPS5412A (en) * | 1977-06-02 | 1979-01-05 | Nippon Koushitsu Touki Kk | Mold for molding green ceramic |
| JPS5614451A (en) * | 1979-07-09 | 1981-02-12 | Agency Of Ind Science & Technol | Manufacture of glass subjected to reflection preventing treatment |
| US4413966A (en) * | 1981-06-26 | 1983-11-08 | Wallace Murray Corporation | Fluid-release mold and the method of manufacturing the same |
| JPS6088B2 (en) * | 1981-07-25 | 1985-01-05 | 雪枝 時津 | Gravity and vacuum filtration device |
| JPS58208005A (en) * | 1982-05-27 | 1983-12-03 | 株式会社イナックス | Sludge casting molding method |
| JPS608010A (en) * | 1983-06-28 | 1985-01-16 | 高木 金一 | Gypsum mold for molding pottery through which mud is injected at high pressure |
| JPS60179212A (en) * | 1984-02-27 | 1985-09-13 | Sintokogio Ltd | Manufacture of cold setting resin product |
| JPS6233601A (en) * | 1985-08-06 | 1987-02-13 | 株式会社イナックス | Sludge casting molding method |
| EP0234360A1 (en) * | 1986-02-20 | 1987-09-02 | Keramik Holding AG Laufen | Casting mould for making ceramic articles |
-
1986
- 1986-07-26 JP JP61176370A patent/JPS6331710A/en active Granted
-
1987
- 1987-07-23 CA CA000542851A patent/CA1304918C/en not_active Expired - Fee Related
- 1987-07-24 DE DE19873724610 patent/DE3724610A1/en active Granted
- 1987-07-24 US US07/077,657 patent/US4913868A/en not_active Expired - Lifetime
- 1987-07-24 IT IT21442/87A patent/IT1222130B/en active
- 1987-07-24 SE SE8702961A patent/SE468380B/en not_active IP Right Cessation
- 1987-07-24 FR FR878710595A patent/FR2601895B1/en not_active Expired - Fee Related
- 1987-07-25 KR KR8708105A patent/KR900003082B1/en not_active IP Right Cessation
- 1987-07-27 GB GB8717757A patent/GB2194751B/en not_active Expired
-
1988
- 1988-02-03 US US07/152,040 patent/US4874304A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| IT1222130B (en) | 1990-09-05 |
| US4874304A (en) | 1989-10-17 |
| IT8721442A0 (en) | 1987-07-24 |
| SE8702961D0 (en) | 1987-07-24 |
| GB2194751B (en) | 1989-12-13 |
| GB8717757D0 (en) | 1987-09-03 |
| US4913868A (en) | 1990-04-03 |
| FR2601895B1 (en) | 1990-11-02 |
| SE468380B (en) | 1993-01-11 |
| DE3724610C2 (en) | 1990-10-25 |
| KR900003082B1 (en) | 1990-05-07 |
| JPH0215365B2 (en) | 1990-04-11 |
| GB2194751A (en) | 1988-03-16 |
| KR880001386A (en) | 1988-04-23 |
| DE3724610A1 (en) | 1988-02-04 |
| FR2601895A1 (en) | 1988-01-29 |
| JPS6331710A (en) | 1988-02-10 |
| SE8702961L (en) | 1988-01-27 |
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| MKLA | Lapsed |